Compliant plate seals for rotary machines

ABSTRACT

A seal assembly for rotary machine is provided. The seal assembly includes multiple compliant plates disposed between a stationary component and a rotary component of the rotary machine, and coupled circumferentially along the stationary component. Each compliant plate comprises a tip configured to be disposed facing the rotary component, and at least one plate slot extending from the stationary component towards the rotary component. The seal assembly also includes at least one annular resistance member configured to be coupled to the stationary component and disposed in the at least one plate slot in the compliant plates and one or more rotor slots or grooves located circumferentially on a surface of the rotary component proximate the tip of each of the plurality of compliant plates.

BACKGROUND

The present application relates generally to seal assemblies for rotary machines and more particularly relates to compliant plate seals for sealing rotor/stator gaps and the like.

Various types of rotary machines such as gas turbine engines, aircraft engines and steam turbines, are known and widely used for power generation, propulsion, and the like. The efficiency of the rotary machines depends in part upon the clearances between the internal components and the leakage of primary and secondary fluids through these clearances. For example, large clearances may be intentionally allowed at certain rotor-stator interfaces to accommodate large, thermally or mechanically-induced, relative motions. Leakage of fluid through these gaps from regions of high pressure to regions of low pressure may result in poor efficiency for the rotary machines. Such leakage may impact efficiency in that the leaked fluids fail to perform useful work.

Different types of sealing systems are used to minimize the leakage of fluid flowing through the rotary machines. The sealing systems between the rotor and stator, are subjected to relatively high temperatures, thermal gradients, and thermal and mechanical expansion and contraction during various operational stages that may increase or decrease the clearance between the rotor and stator. For example, traditional labyrinth seals that are assembled with a very tight clearance, may rub during start-up transient, and the resulting large clearances during steady state operation may lead to poor performance at steady state operation. Conventional leaf seals provide better sealing, but are prone to seal rubbing, and seal wear and tear. Moreover, the conventional seals are not adaptable depending upon the operating pressure, and type of machine.

There is therefore a desire of a rotary machine seal wherein the gap between the seal and the rotating component is self-adjustable, depending on the operating condition of the machine.

BRIEF DESCRIPTION

In accordance with an embodiment of the invention, a seal assembly for a rotary machine is provided. The seal assembly includes multiple compliant plates disposed between a stationary component and a rotary component of the rotary machine, and coupled circumferentially along the stationary component. Each compliant plate comprises a tip configured to be disposed facing the rotary component, and at least one plate slot extending from the stationary component towards the rotary component. The seal assembly also includes at least one annular resistance member configured to be coupled to the stationary component and disposed in the at least one plate slot in the compliant plates and one or more rotor slots or grooves located circumferentially on a surface of the rotary component proximate the tip of each of the plurality of compliant plates.

In accordance with an embodiment of the invention, a rotary machine is provided. The rotary machine includes a stationary component, a rotary component and a seal assembly disposed between the stationary component and the rotary component. The seal assembly includes multiple compliant plates disposed between the stationary component and the rotary component, and coupled circumferentially along the stationary component. Each compliant plate includes a tip configured to be disposed facing the rotary component, and at least one plate slot extending from the stationary component towards the rotary component. Further, the seal assembly includes at least one annular resistance member configured to be coupled to the stationary component and disposed in the at least one plate slot in the compliant plates. The seal assembly further includes one or more rotor slots or grooves located circumferentially on a surface of the rotary component proximate the tip of each of the plurality of compliant plates.

In accordance with an embodiment of the invention, a method of manufacturing a seal assembly is provided. The method includes attaching a plurality of compliant plates circumferentially along the stationary component such that the plurality of compliant plates are disposed between the stationary component and a rotary component, wherein each compliant plate comprises a tip configured to be disposed facing the rotary component, a tip slot in a portion of the tip proximate the high pressure region, and at least one plate slot extending from the stationary component towards the rotary component. The method includes attaching at least one annular resistance member to the stationary component and disposing in the at least one plate slot in the compliant plates. The method also includes providing one or more rotor slots or grooves circumferentially located on a surface of the rotary component proximate the tip of each of the plurality of compliant plates.

DRAWINGS

These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

FIG. 1 is a partial perspective view of a rotary machine with a compliant plate seal assembly in accordance with an exemplary embodiment of the present invention.

FIG. 2 is cross sectional view of a compliant plate seal assembly in accordance with an exemplary embodiment of the present invention

FIG. 3 is the cross sectional view of a seal assembly in accordance with another embodiment of the present invention.

FIG. 4 illustrates a cross sectional view of the seal assembly in accordance with an embodiment of the present invention.

FIG. 5 illustrates a cross sectional view of the seal assembly in accordance with an embodiment of the present invention.

FIG. 6 illustrates a cross sectional view of the seal assembly in accordance with another embodiment of the present invention.

FIG. 7 illustrates a cross sectional view of a seal assembly in accordance with yet another embodiment of the present invention.

FIG. 8 illustrates a plot of a hydrostatic torque on the compliant plate versus the tip clearance in accordance with an embodiment of the present invention.

FIG. 9 illustrates a plot of a hydrostatic torque on the compliant plate with inlet rotor slots or groove versus the tip clearance in accordance with an embodiment of the present invention.

FIG. 10 is flow chart illustrating exemplary steps involved in method of manufacturing a seal assembly for a rotary machine in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION

When introducing elements of various embodiments of the present invention, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Further, the term “lift off” may be defined as an increase in a tip clearance due to radially outward motion of the compliant plates. Similarly, the term “blow down” may refer to as a decrease in the tip clearance, due to the radially inward motion of the seal. Any examples of operating parameters are not exclusive of other parameters of the disclosed embodiments. Embodiments presented herein relate to a seal assembly for a turbo machine or rotary machine. The seal assembly disclosed herein may be used with any turbo machine such as, but not limited to, gas turbine, steam turbine, compressors, or aircraft engines. The turbo machine includes a stationary component such as a stator, or housing, or any other stationary part disposed proximate to a rotary component. The rotary component may include a rotor of the turbo machine. The turbo machine may typically include a series of alternate stator and rotor stages. A pressurized fluid is passed through the turbo machine through the series of stator and rotor stages. The rotor is generally configured to rotate upon the passage of the pressurized fluid through the turbo machine. Alternately, the rotation of the rotor may cause the flow of the fluid or pressurization of the fluid.

FIG. 1 illustrates a perspective view of a rotary machine 10 (not fully shown) in accordance with an embodiment of the present invention. The rotary machine 10 includes a stationary component 12, a rotary component 14 and a seal assembly 16. The seal assembly 16 includes multiple compliant plates 18 disposed between the stationary component 12 and the rotary component 14 of the rotary machine 10. The compliant plates 18 are attached or welded to the stationary component 12. The seal assembly 16 is configured to seal a gap between the stationary component 12 and the rotary component 14. Each compliant plate 18 has a root 20 disposed proximate to the stationary component 12 and a tip 22 disposed proximate to the rotary component 14. The tip 22 refers to the free end of the compliant plate 18 disposed proximate to the rotary component 14. A gap 24 between successive compliant plates 18 increases from an inner diameter of the seal assembly to an outer diameter of the seal assembly. In an embodiment, the plurality of compliant plates 18 are oriented at an angle θ with respect to a tangential direction of the rotary component 14. The value of the angle θ may be in the range of about thirty degrees to about sixty degrees.

Each compliant plate 18 further includes an intermediate plate slot 26 extending from the root 20 towards the tip 22. A resistance member 28 is disposed in the intermediate plate slots 26 of the plurality of compliant plates 18. In an embodiment, the resistance member 28 is annular in shape and extends circumferentially about the stationary component 12. The resistance member 28 may be a continuous ring. In another embodiment, the resistance member 28 may include a plurality of circumferential segments assembled to form a ring.

FIG. 2 illustrates a cross sectional view of the seal assembly 16 in accordance with an embodiment of the present invention. The seal assembly 16 is disposed between a high pressure region 30 and a low pressure region 32. The seal assembly 16 separates the high pressure region 30 of the rotary machine from the low pressure region 32. FIG. 2 further illustrates the resistance member 28 provided inside the intermediate plate slot 26 of the compliant plate 18. The intermediate plate slot 26 includes a first surface 34 that faces a leading surface 36 of the resistance member 28, and a second surface 38 that faces a trailing surface 40 of the resistance member 28. A front gap 42 is defined between the first surface 34 of the compliant plate 18 and the leading surface 36 of the resistance member 28. Similarly, a back gap 44 is defined between the second surface 38 of the compliant plate 18 and the trailing surface 40 of the resistance member 28. A bridge gap 50 is defined between the lower surface 46 of the resistance member 28 and the lower surface 48 of the intermediate plate slot 70.

The seal assembly 16 may further include a front ring 52 and a back ring 54. The front ring 52 and the back ring 54 may be coupled to the stationary component 12 of the rotary machine 10. The front ring 52 extends circumferentially across a leading surface 56 of the compliant plates 18 and the back ring 54 extends circumferentially along the trailing surface 58 of the compliant plates 18. A gap defined between the front ring 52 and the leading surface 56 is referred to as a front ring gap 60, and a gap between the back ring 54 and the trailing surface 58 is referred to as a back ring gap 62. FIG. 2 also shows a tip clearance 63 that may allow a first leakage flow 51 of the pressurized fluid from the high pressure region 30 to the low pressure region 32. A second leakage flow 53 of the pressurized fluid occurs through the gaps between adjacent compliant plates 18. In this embodiment as shown in FIG. 2, the seal assembly 16 includes multiple rotor slots 64 located circumferentially on a surface of the rotary component 14 proximate the tip 22 of each of the multiple compliant plates 18 towards the high pressure side 30. In another embodiment as shown in FIG. 3, a seal assembly 17 includes a rotor groove 66 located circumferentially on a surface of the rotary component 14 proximate the tip of each of the plurality of compliant plates 18 towards the high pressure side 30 of the rotary machine 10 (shown in FIG. 1). In a non-limiting example, a width of the multiple rotor slots 64 or the groove 66 may extend upto half of a span of the compliant plate 18 in an axial direction. Further, a height of the multiple rotor slots 64 or the rotor groove 66 may vary from about 30 mils to about 200 mils.

During operation of the rotary machine 10 at low clearances between the seal assembly 16 and the rotary component 14, the multiple rotor slots 64 causes the compliant plates 18 for lift off and prevents rubbing of the tip 22 of the compliant plate 18 with the surface of the rotary component 14. The multiple rotor slots 64 towards the high pressure region 30 causes the first and second leakage flows 51, 53 of the pressurized fluid to generate pressure forces acting towards the tip 22 of the compliant plates 18 such that a sum of total hydrostatic torque over the entire surface of the compliant plate 18 is a lift torque.

Similarly, during operation of the rotary machine 10 (shown in FIG. 1) at low clearances between the seal assembly 17 and the rotary component 14, the rotor groove 66 towards the high pressure region 30 causes the compliant plates 18 for lift off and prevents rubbing of the tip 22 of the compliant plate 18 with the surface of the rotary component 14. The rotor groove 66 towards the high pressure region 30 causes the first and second leakage flows 51, 53 of the pressurized fluid to generate pressure forces acting towards the tip 22 of the compliant plates 18 such that a sum of total hydrostatic torque over the entire surface of the compliant plate 18 is a lift torque. The lift torque of the compliant plate 18 at lower clearances due to presence of multiple rotor slots 64 or groove 66 is discussed further with respect to a plot 100 (torque versus clearance graph) of FIG. 8. Advantageously, at low differential pressure, the seal assemblies 16, 17 provide more stability by reducing flow-induced vibrations of the compliant plates and allowing for an optimal clearance between the tip and rotor surface. This is further discussed with respect to a plot 200 as shown in FIG. 9.

FIG. 4 illustrates a cross sectional view of the seal assembly 19 in accordance with an embodiment of the present invention. As shown, the seal assembly 19 includes multiple rotor slots 68 located circumferentially on a surface of the rotary component 14 proximate the tip 22 of each of the plurality of compliant plates 18 towards the low pressure side 32 of the rotary machine 10 (shown in FIG. 1). During operation of the rotary machine 10 at large clearances between the seal assembly 19 and the rotary component 14, the multiple rotor slots 68 causes blow down of the compliant plates 18 and prevent excessive leakages between the tip 22 of compliant plates 18 and the rotor surface. The multiple rotor slots 68 towards the low pressure region 32 causes the first and second leakage flows 51, 53 of the pressurized fluid to generate pressure forces acting radially inwards towards the tip 22 of the compliant plates 18 such that a sum of total hydrostatic torque over the entire surface of the compliant plate 18 is a blow down torque.

In another embodiment as shown in FIG. 5, a seal assembly 21 may include a rotor groove 70 located circumferentially on a surface of the rotary component 14 proximate the tip 22 of each of the plurality of compliant plates 18 towards the low pressure region 32 of the rotary machine 10 (shown in FIG. 1). The rotor groove 70 towards the low pressure region 32 causes the first and second leakage flows 51, 53 of the pressurized fluid to generate pressure forces acting towards the tip 22 of the compliant plates 18 such that a sum of total hydrostatic torque over the entire surface of the compliant plate 18 is a blow down torque. The lift torque of the compliant plate 18 at lower clearances due to presence of multiple rotor slots 68 or groove 70 is discussed further with respect to a plot 100 (torque versus clearance graph) of FIG. 8. In an exemplary embodiment, the width of the multiple rotor slots 68 or the groove 70 may extend upto half of a span of the compliant plate 18 in an axial direction. Further, the height of the multiple rotor slots 68 or the groove 70 may vary from about 30 mils to about 200 mils.

In another embodiment, as shown in FIG. 6, a seal assembly 23 includes a tip slot 27 on the tip 22 of the compliant plate 18 along with multiple slots or groove 25 towards high pressure region 30 and cause lift off of the compliant plates 18 at low tip clearances. In another embodiment (not shown), a seal assembly may include a tip slot on the tip 22 of the compliant plate 18 along with multiple slots or groove towards low pressure region 32 causing blow down of the complaint plates at large clearances. The tip slot shown in FIG. 8 is triangular shaped. In one embodiment, the width of both the tip slot 27 and the multiple slots or groove 25 may extend upto half of a span of the compliant plate 18 in an axial direction. Further, the height of the tip slot 27 or multiple slots or the groove 25 may vary from about 30 mils to about 200 mils

FIG. 7 shows another embodiment of a seal assembly 29 that includes a multiple triangular-shaped rotor slots 31 or groove on the rotor towards the high pressure region 30 for causing lift off of the compliant plates 18 at low tip clearances. In another embodiment (not shown), a seal assembly may include a multiple triangular-shaped rotor slots 31 or groove on the rotor towards low pressure region 32 causing blow down of the complaint plates at large clearances.

In other embodiments (not shown), the shape and size of the tip slot of the compliant plate or the shape and size of the rotor slots or groove on the rotor surface as discussed above (FIG. 2 to FIG. 7) may include a triangular shape or rectangular shape or partial hexagonal shape or any other geometrical shape for allowing the compliant plate to settle at a desired tip clearance as per the optimal performance of the rotary machine.

FIG. 8 illustrates a plot 100 of a hydrostatic torque on the compliant plate versus the tip clearance in accordance with an embodiment of the present invention. It is to be noted that the plot 100 is a result from data generated from a computational fluid dynamics (CFD) simulation. The plot 100 illustrates the effect of providing multiple rotor slots or groove on the rotor surface proximate the high pressure region or the low pressure of the rotary machine. The tip of the compliant plate is subjected to a hydrostatic pressure resulting in a hydrostatic torque on the compliant plate. The hydrostatic torque (in Newton-meters) is represented along the Y axis and the clearance (in inches) is represented along the X axis. FIG. 8 includes three curves 102, 104 and 106. Curve 102 represents the variation of hydrostatic torque with the tip clearance for a normal compliant plate and rotor (without slots or groove on rotor surface), curve 104 represents the variation of hydrostatic torque with the tip clearance for a compliant plate and a rotor surface with multiple rotor slots or groove towards the high pressure region and curve 106 represents the variation of hydrostatic torque with the tip clearance for a complaint plate and a rotor surface with multiple rotor slots or groove towards the low pressure region. A positive hydrostatic torque implies that there is a net lifting torque on the compliant plate. The compliant plates settle at a clearance wherein the net hydrostatic torque is zero. As evident from FIG. 8, a normal compliant plate and rotor surface (without slots or groove on the rotor surface) settles at a tip clearance represented by point 108, the compliant plate and the rotor surface with multiple rotor slots or groove towards high pressure region settles at a tip clearance represented by point 110 and the compliant plate and the rotor surface with multiple rotor slots or groove towards low pressure region settles at a tip clearance represented by point 112. Hence, the equilibrium tip clearance of the seal assembly (or the zero torque points 108, 110, and 112) may be varied by the designer by providing the multiple rotor slots or groove on rotor surface towards either the high or low pressure region for providing lift off of complaint plates at low clearances and blow down of compliant plates at large clearances.

FIG. 9 illustrates a plot 200 of a hydrostatic torque on the compliant plate versus the tip clearance in accordance with an embodiment of the present invention. The plot 100 illustrates another advantage of providing multiple rotor slots or groove on the rotor surface proximate the high pressure region of the rotary machine. As discussed earlier, the tip of the compliant plate is subjected to a hydrostatic pressure resulting in a hydrostatic torque on the compliant plate and further causing the compliant plates to settle at a clearance where the net hydrostatic torque is zero. However, at low differential pressure, the seal assembly may be unstable for a normal complaint plate and rotor assembly (without slots or groove on the rotor towards high pressure region) unlike the seal assemblies 16, 17 (shown in FIG. 2, 3) that are stable under low differential pressure. As shown, the hydrostatic torque (in Newton-meters) is represented along the Y axis and the clearance (in inches) is represented along the X axis. FIG. 7 includes two curves 202, and 204. Curve 202 represents the variation of hydrostatic torque with the tip clearance for the normal compliant plate and rotor (without slots or groove on rotor surface towards high pressure region). Further the curve 202 clearly shows intersecting the zero torque line at two points 206 and 208. This implies the fluttering nature of the normal compliant plate and rotor seal assembly. On the other hand, the curve 204 representing the variation of hydrostatic torque with the tip clearance for a compliant plate and a rotor surface with multiple rotor slots or groove towards the high pressure region intersects the zero torque line at one point 210, thereby implying a stable seal assembly.

In one embodiment, a rotary machine is provided. The rotary machine includes a stationary component, a rotary component and a seal assembly disposed between the stationary component and the rotary component. The seal assembly includes multiple compliant plates disposed between the stationary component and the rotary component, and coupled circumferentially along the stationary component. Each compliant plate includes a tip configured to be disposed facing the rotary component, and at least one intermediate plate slot extending from the stationary component towards the rotary component. Further, the seal assembly includes at least one annular resistance member configured to be coupled to the stationary component and disposed in the at least one intermediate plate slot in the compliant plates. The seal assembly further includes one or more rotor slots or grooves located circumferentially on a surface of the rotary component proximate the tip of each of the plurality of compliant plates. Further, the one or more rotor slots or grooves are located circumferentially on the surface of the rotary component towards a high pressure side of the rotary machine for allowing the plurality of compliant plates to lift off at low tip clearances with the surface of the rotary component and allowing stability of the plurality of compliant plates during operation of the rotary machine. Furthermore, in another embodiment, the one or more rotor slots or grooves are located circumferentially on the surface of the rotary component towards a low pressure side for allowing the plurality of compliant plates to blow-down during large tip clearances with the surface of the rotary component.

FIG. 10 is flow chart 300 of a method of manufacturing a seal assembly for a rotary machine in accordance with an embodiment of the present invention. At step 302, the method includes attaching a plurality of compliant plates circumferentially along the stationary component such that the plurality of compliant plates are disposed between the stationary component and a rotary component, wherein each compliant plate comprises a tip configured to be disposed facing the rotary component, and at least one intermediate plate slot extending from the stationary component towards the rotary component. At step 304, the method also includes attaching at least one annular resistance member to the stationary component and disposing in the at least one intermediate plate slot in the compliant plates. Further, the method includes providing one or more rotor slots or grooves circumferentially located on a surface of the rotary component proximate the tip of each of the plurality of compliant plates at step 306. Furthermore, in one embodiment, the method includes providing the one or more rotor slots or grooves on the surface of the rotary component towards a high pressure side for allowing the plurality of compliant plates to lift off at low tip clearances with the surface of the rotary component. In another embodiment, the method includes providing the one or more rotor slots or grooves on the surface of the rotary component towards a low pressure side for allowing the plurality of compliant plates to blow-down during large clearances with the surface of the rotary component.

Advantageously, the present compliant seal assemblies are reliable, robust seal for several locations in rotating machinery with large pressure drops and large transients. The seal assemblies are also economical to fabricate. The non-contact operation of the seals makes them especially attractive for the large rotor transient locations. The present invention allows adjusting of the compliant seals equilibrium point at which the net hydrostatic torque acting on the compliant plates is zero, thus enabling a lower tip clearances or a larger tip clearances as per requirement. Further, the present invention prevents fluttering of the compliant plates and therefore provides stability.

Furthermore, the skilled artisan will recognize the interchangeability of various features from different embodiments. Similarly, the various method steps and features described, as well as other known equivalents for each such methods and feature, can be mixed and matched by one of ordinary skill in this art to construct additional systems and techniques in accordance with principles of this disclosure. Of course, it is to be understood that not necessarily all such objects or advantages described above may be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize that the systems and techniques described herein may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.

While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention. 

1. A seal assembly for a rotary machine, the seal assembly comprising: a plurality of compliant plates disposed between a stationary component and a rotary component of the rotary machine, and coupled circumferentially along the stationary component, wherein each compliant plate comprises a tip configured to be disposed facing the rotary component, and at least one intermediate plate slot extending from the stationary component towards the rotary component; at least one annular resistance member configured to be coupled to the stationary component and disposed in the at least one intermediate plate slot in the compliant plates; and one or more rotor slots or grooves located circumferentially on a surface of the rotary component proximate the tip of each of the plurality of compliant plates.
 2. The seal assembly of claim 1, wherein the one or more rotor slots or grooves are located circumferentially on the surface of the rotary component towards a high pressure side of the rotary machine for allowing the plurality of compliant plates to lift off at low tip clearances with the surface of the rotary component.
 3. The seal assembly of claim 1, wherein the one or more rotor slots or grooves are located circumferentially on the surface of the rotary component towards a low pressure side for allowing the plurality of compliant plates to blow-down during large tip clearances with the surface of the rotary component.
 4. The seal assembly of claim 1, wherein the one or more rotor slots or grooves are configured to effect a pressure distribution on the tip of the compliant plates such that a defined clearance is established between the tip of the plurality of compliant plates and the rotary component during operation of the rotary machine.
 5. The seal assembly of claim 1, wherein each of the one or more rotor slots comprise a rectangular shaped slot.
 6. The seal assembly of claim 1, wherein each of the one or more rotor slots comprise a triangular shaped slot.
 7. The seal assembly of claim 1, wherein each of the one or more rotor grooves comprise a rectangular shaped groove.
 8. The seal assembly of claim 1, wherein each of the one or more rotor grooves comprise a triangular shaped groove.
 9. The seal assembly of claim 1, wherein each of the plurality of compliant plates comprise a tip slot in a portion of the tip proximate a high pressure side of the rotary machine.
 10. The seal assembly of claim 9, wherein the tip slot is a rectangular shaped slot or a triangular shaped slot.
 11. The seal assembly of claim 9, wherein the tip slot extends from a side of the tip proximate the high pressure region towards the low pressure region.
 12. The seal assembly of claim 9, wherein the tip slot is configured to effect a pressure distribution on the tip of the compliant plates such that a defined clearance is established between the tip of the plurality of compliant plates and the rotary component during operation of the rotary machine.
 13. The seal assembly of claim 1, wherein the annular resistance member comprises a continuous ring.
 14. The seal assembly of claim 1, wherein the annular resistance member comprises a plurality of segments assembled to form a ring.
 15. A rotary machine comprising: a stationary component; a rotary component; and a seal assembly disposed between the stationary component and the rotary component, the seal assembly comprising: a plurality of compliant plates disposed between the stationary component and the rotary component, and coupled circumferentially along the stationary component, wherein each compliant plate comprises a tip configured to be disposed facing the rotary component, and at least one intermediate plate slot extending from the stationary component towards the rotary component; at least one annular resistance member configured to be coupled to the stationary component and disposed in the at least one intermediate plate slot in the compliant plates; and one or more rotor slots or grooves located circumferentially on a surface of the rotary component proximate the tip of each of the plurality of compliant plates.
 16. The rotary machine of claim 15, wherein the one or more rotor slots or grooves are located circumferentially on the surface of the rotary component towards a high pressure side of the rotary machine for allowing the plurality of compliant plates to lift off at low tip clearances with the surface of the rotary component and allowing stability of the plurality of compliant plates during operation of the rotary machine.
 17. The turbo machine of claim 15, wherein the one or more rotor slots or grooves are located circumferentially on the surface of the rotary component towards a low pressure side for allowing the plurality of compliant plates to blow-down during large tip clearances with the surface of the rotary component.
 18. A method of manufacturing a seal assembly for a rotary machine, the method comprising: attaching a plurality of compliant plates circumferentially along the stationary component such that the plurality of compliant plates are disposed between the stationary component and a rotary component, wherein each compliant plate comprises a tip configured to be disposed facing the rotary component, and at least one intermediate plate slot extending from the stationary component towards the rotary component; attaching at least one annular resistance member to the stationary component and disposing in the at least one intermediate plate slot in the compliant plates; and providing one or more rotor slots or grooves circumferentially located on a surface of the rotary component proximate the tip of each of the plurality of compliant plates.
 19. The method of manufacturing of claim 18, further comprising providing the one or more rotor slots or grooves on the surface of the rotary component towards a high pressure side for allowing the plurality of compliant plates to lift off at low tip clearances with the surface of the rotary component.
 20. The method of manufacturing of claim 18, further comprising providing the one or more rotor slots or grooves on the surface of the rotary component towards a low pressure side for allowing the plurality of compliant plates to blow-down during large clearances with the surface of the rotary component. 